How to speed up iOS start on MacBook after password entry?

iOS is not running on Macs, Mac run macOS. Furthermore, please try this

To speed up your Mac after you enter your password, reduce the number of apps and background tasks that start automatically. 

Remove Unnecessary Login Items

• Open System Settings on your Mac.
• Go to General, then select Login Items (or Login Items & Extensions).
• Look under Open at Login and select any app you do not need right away.
• Click the minus (-) button to remove it.
• Scroll down to Allow in the Background and turn off helper tools or utilities from apps you rarely use.
• Stop windows from reopening by unchecking Reopen windows when logging back in whenever you restart or shut down your Mac. 

Many times such issues are due to third party software. Usual culprits are anti-virus software, cleaning & optimizer apps, and third party security software. None of these are needed on a Mac and will usually cause more problems than they solve since they interfere with the normal operation of macOS. If you have any of these types of apps installed, then uninstall them by following their developers instructions.

You also need to make sure all your third party apps are actually fully compatible with Golden Gate. Sometimes it can take weeks or months (worst case years) for third party apps to be fully compatible with a new OS. I find it is usually best to wait a few months before installing a new version of any OS in order to let all the release day bugs to be fixed and to give third party developers time to release fully compatible versions of their apps. Make sure all of your third party apps are completely up to date and ensure they are also fully compatible with macOS 27.

There also seems to be some issues with macOS using up significant amounts of storage space so you may want to check how much Free storage space you actually have at the moment. Apple Intelligence is taking away about 35GB of storage which most people are not aware would happen.

People should always have at least 20% of Free space, but I highly recommend having 80GB-100GB Free since even this can sometimes disappear very quickly with seemingly simple workloads (more is needed for more system intensive workloads). Unfortunately the only place where the Free storage space is shown is in Disk Utility. Ignore the very misleading "Available" storage value shown everywhere in macOS as it is not synonymous with Free.

Plus it can take a few days for things to setting down after a major OS upgrade with lots of background maintenance tasks.

Also try disconnecting all external devices just in case one of them may be causing a problem.

Are you asking about the iPhone iOS or the mac macOS...?

if you just upgraded to the new macOS 27, it is recommenced to shutdown and restart more than once to sort issues and then compare your results...

>Shut Down

ref: Log out, sleep, wake, restart or shut down your Mac

Shut down or restart your Mac - Apple Support